Common Bacterial and Fungal Infection of the Skin Flashcards
Gram (+) cocci Arranged in clusters Most Pathogenic of all Staphylococci Coagulase(+) Catalase (+) Has PROTEIN A (antiphagocytic) beta hemolysis on BAP
Staphylococcus Aureus
Superficial inflammation of hair follicles.
Small Erythematous papules/pustules associtaed with follicles
Folliculitis
Commonly known as boil
Deeper form of folliculitis
Resolves upon spontaneous drainage
Furuncle
When furuncles coalesce
Found in thick skin
May be seen in diabetic patients
Carbuncles
Also called as ACNE INVERSA
disorder of the apocrine glands
Chronic disorder
Extensive scarrin, with multiple sinuses in and around the axilla
Hidradenitis Suppurutiva
Yellowish crust on the skin
Impetigo
Also called as ritter’s disease or pemphigus neonatorum
Generalized skin manifestation
Most aggressive form of Staphylococcal infection
The production of exfolatin by bacteria causues this syndrome
Staphylococcal Scalded Skin Syndrome
Laboratory Dx of S. aureus
Gram stain: (+)
BAP and MSA
Coagulase and Catalase (+)
treatment of S. aureus
Penicillin
or Vancomycin
G(+) cocci in chains Strict Parasite Man is the only significant reservoir Commonly presents as sore throat Most serious Streptococcal pathogen Sensitive bacitracin Beta Hemolytic
Streptococcus pyogenes (Group A)
The only significant reservoir for s. pyogenes
Man (nasopharyngeal)
transmission of S. pyogenes
Direct/droplet
Non infectious sequelae of S. pyogenes
RHD, AGN
Impetigo in S. pyogenes
with yellow crusting
Infection of epidermis which extends to the dermis, with characteristic “punched” out lesions
Ecthyma
Shiny, swollen, red and painful
May become bullous
treated with 1st Gen cephalosporin
Cellulitis
Deep seated infection
Emergency case
Violaceous discoloration of the skin
Swelling within 24-48 hours, acute infection
Lesions darken; 4th-5th day then becomes gangrenous
Necrotizing Fascitis
Organisms associtaed with Nec Fas
peptostreptococci, Bacteroides, gram (-) rods and streptococcus
Laboratory Dx of Streptococcus
G(+) cocci in chains
B-hemolysis
Bacitracin Sensitive (0.02 ug)
Screening Test: Latex Agglutination (Ig monoclonal to C- carbohydrate)
Treatment for Streptococcus
Penicillin (cell wall inhibitors)
Low resistance against PEN (Benzathine Penicillin, Pen G or Pen V)
Alternative: Macrolides (Erythromycin)
Hansen’s disease
Acid fast Bacillus
Cannot be cultured in vitro
Mycobacterium leprae
M. Leprae can be propagated in
Nude mice (no T cells)
Monkey
9-banded armadillo
Frequently affected nerves in Hansen’s disease
Median, Radial, ulnar, Popliteal, Perineal
Paucibacillary
Strong CMIR HIR normal granuloma formation Anesthetic Not Infectious treatment: 9 months
Multibacillary
CMIR is weak (anergy) HIR Over reactive leads - Erythema nodosum leprossum No granuloma Infectious treatment : 3 years
Signs and Symptoms of Hansen’s disease
Area of discoloration Anesthesia Loss of hair in affected skin No sweating in the area Thickened nerve Area not pruritic Muscle Weakness
treatment for Hansen’s disease
Dapsone
Rifampicin
Clofaximine - darkening of the skin
G(-) aerobic bacilli
opportunistic pathogen
grape like or tortilla odor in vitro
Oxidase (+)
Pseudomonas Aeruginosa
Definitive Diagnosis of p. Aeruginosa
Pyocyanin and fluorescein
Ability to grow at 42 degrees
Paronychial infection that develop in individuals whose hands are frequently submerged in water
Green Nail syndrome
occur in patients with decubitus ulcer, eczema and tinea pedis. These infections may have a Characteristic blue-green exudate and fruity odor
Secondary wound infections
Pruritic follicular, maculopapular, vesicular or pustular lesions on any part of the body that was immersed in water
HOT TUB or swimming pool folliculitis
Pseudomonal bacteremia produces well-recognized but uncommon distinctive skin lesion
Hemorrhagic vesicles and pustules that evolve into necrotic ulcers
Ecthyma gangrenosum
Treatment for P. aeruginosa
Double antibiotic therapy
Surgical removal of eschars, debridement of necrotic tissue, or in severe cases, amputaion may be required
Causative agent for Fish tank granuloma
M. marinum
Skin abscesses at the site of self administered insulin injections n the thigh of a diabetic patient
M. chelonae
tropical Ulcer
Fusobacterium fusiformis
Gram(+) rod
spore forming
Skin infection with marked necrosis and edema of tissue
Bacillus anthracis
Gas gangrene
Clostridium perfringens
Animal bite infection
Pasteurella multicoda
Anthrophilic fungus and is the most common and widely distributed dermatophyte of humans
Trichophytum rubrum
Common saprophytic fungus believed to occur in soil, compost, humus, and on wood in humid tropical and subtropical regions. Familial spread of infection is reported
Tinea Nigra
